From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 99DBEC43603 for ; Wed, 18 Dec 2019 02:42:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6D90921D7D for ; Wed, 18 Dec 2019 02:42:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726613AbfLRCmt (ORCPT ); Tue, 17 Dec 2019 21:42:49 -0500 Received: from mga02.intel.com ([134.134.136.20]:45366 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726496AbfLRCmt (ORCPT ); Tue, 17 Dec 2019 21:42:49 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga002.jf.intel.com ([10.7.209.21]) by orsmga101.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 17 Dec 2019 18:42:48 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.69,327,1571727600"; d="scan'208";a="227712787" Received: from allen-box.sh.intel.com (HELO [10.239.159.136]) ([10.239.159.136]) by orsmga002.jf.intel.com with ESMTP; 17 Dec 2019 18:42:46 -0800 Cc: baolu.lu@linux.intel.com, "Tian, Kevin" , Raj Ashok , Yi Liu , Eric Auger , Yi L Subject: Re: [PATCH v8 02/10] iommu/vt-d: Add nested translation helper function To: Jacob Pan , iommu@lists.linux-foundation.org, LKML , Joerg Roedel , David Woodhouse References: <1576524252-79116-1-git-send-email-jacob.jun.pan@linux.intel.com> <1576524252-79116-3-git-send-email-jacob.jun.pan@linux.intel.com> From: Lu Baolu Message-ID: <6192b57c-12ab-ec6c-ab95-d9b9bff3efad@linux.intel.com> Date: Wed, 18 Dec 2019 10:41:53 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.2.1 MIME-Version: 1.0 In-Reply-To: <1576524252-79116-3-git-send-email-jacob.jun.pan@linux.intel.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi again, On 12/17/19 3:24 AM, Jacob Pan wrote: > +/** > + * intel_pasid_setup_nested() - Set up PASID entry for nested translation > + * which is used for vSVA. The first level page tables are used for > + * GVA-GPA or GIOVA-GPA translation in the guest, second level page tables > + * are used for GPA-HPA translation. > + * > + * @iommu: Iommu which the device belong to > + * @dev: Device to be set up for translation > + * @gpgd: FLPTPTR: First Level Page translation pointer in GPA > + * @pasid: PASID to be programmed in the device PASID table > + * @pasid_data: Additional PASID info from the guest bind request > + * @domain: Domain info for setting up second level page tables > + * @addr_width: Address width of the first level (guest) > + */ > +int intel_pasid_setup_nested(struct intel_iommu *iommu, > + struct device *dev, pgd_t *gpgd, > + int pasid, struct iommu_gpasid_bind_data_vtd *pasid_data, > + struct dmar_domain *domain, > + int addr_width) > +{ > + struct pasid_entry *pte; > + struct dma_pte *pgd; > + u64 pgd_val; > + int agaw; > + u16 did; > + > + if (!ecap_nest(iommu->ecap)) { > + pr_err("IOMMU: %s: No nested translation support\n", > + iommu->name); > + return -EINVAL; > + } > + > + pte = intel_pasid_get_entry(dev, pasid); > + if (WARN_ON(!pte)) > + return -EINVAL; > + > + pasid_clear_entry(pte); In some cases, e.g. nested mode for GIOVA-HPA, the PASID entry might have already been setup for second level translation. (This could be checked with the Present bit.) Hence, it's safe to flush caches here. Or, maybe intel_pasid_tear_down_entry() is more suitable? Best regards, baolu